A couple of SDS questions

The house we've just moved into has a condensation problem in the loft. Not surprising really since at some time it's been made just about airtight by packing the 4 inch high gap between the top of the walls and the underside of the roof with a mixture of stones embedded in mortar about 8 inches thick.

It looks as though the simplest cure will be to drill lots of 1 inch holes through the mortar and stones. This is obviously not a task for my conventional B&D hammer drill so I'm using this job to justify treating myself to a new SDS drill which should take this sort of thing in it's stride.

I understand that an SDS bit should have a much longer life than a conventional masonry bit but what I don't know is just how much life. Assuming that I punch 4 holes between each pair of roof timbers I'm going to have over 150 holes to drill. Should I expect to consume a number of expensive long bits in the process or would a single bit survive this sort of treatment?

I'm still trying to decide on which machine to buy. The Makita HR2450 at

120 quid from Screwfix is tempting and has had favourable mention here. On the other hand the Bosch PBH2200RE with a slightly lower spec at 90 quid from Argos looks good value. Detailed specs for the Bosch PBH2200RE are hard to find (it doesn't even exist on the Bosch web site) but from what I've found so far I suspect that (unlike the Makita) it might not have a safety clutch. Could anyone confirm if this is the case or not, or even suggest any alternative machine in this price range with rotation stop, hammer stop, safety clutch and 20-25mm drilling capacity in concrete?
Reply to
Mike Clarke
Loading thread data ...

A single good quality bit, no problem.

I have the DeWalt 566, and have been very happy with it. Having said that, I'm sure the Makita is a good tool. It wasn't out when I bought the DW.

Reply to
Grunff

I would expect no to only need one bit, and have life in it at the end, unless I got a really cheep nasys drill bit.

I guess you are thiniking of buying a 1m bit so you can drill when you are some distance from the object you are drilling, making it a more comfortable job.

I have a 1m bit, and a 600mm bit, and a short bit (my walls are 750mm thick), I drill with the shortest bit I can, as starting a hole with a

1 m bit is hard work, the end tneds to wander arround. If you have rought stuff to fill in and accuracy is not important this is much less of an issue, however it still takes some control.

I would not like to tackle this job, SDS drills are heavy, the location is terrible, ventilation is non existant, and stuff to stand/sit on might not be too good. Good luck with it.

Reply to
Rick Dipper

For starters I'd been considering getting the 18 quid assorted set from Screwfix (No. 80874) which includes a 20 x 450mm bit. I don't know if these count as nasty but if the big bit wears out the rest of the set would provide a reasonable collection for other lighter jobs and hopefully just one quality replacement bit should finish the job.

The inside surface is quite rough with bits of stone sticking out here and there so I'll bear that in mind.

I discovered the condensation as I was boarding the loft floor with chipboard and installing lighting to get more storage space so at least I've got a decent floor to within about 1 foot of the edge. With the fairly steep roof I can sit or kneel quite close to the eaves in reasonable comfort and have enough light to see what I'm doing so I'm hoping it won't be too bad if I avoid working on a hot sunny day when it gets like an oven.

Reply to
Mike Clarke

Wow - doesn't sound too simple to me! Can't you install some ventilation in the shape of airbricks, or tile vents?

David

Reply to
Lobster

That was my first thought but I'd have to bash out quite a lot of the mortar and stone mix to put vents in, about 40 rectangular holes if I put one brick between each pair of joists on 2 sides of the roof. I don't fancy doing it from inside because space is a bit tight for swinging a club hammer and I'd be hammering rubble into the wedge shaped gap under the roof with a risk of damaging it. Although it's a bungalow and I can get up to the outside eaves quite easily the overhang of the roof and the fascia hinder access to attack it from there with a hammer and chisel.

The roof is flat cement tiles (possibly asbestos cement) laid on top of what looks like 6 x 1 timber planks so there'd be quite a bit of disturbance to fit tile vents. If I make a mess of that I could end up with an expensive roof repair job.

It's going to be a tedious job and there could well be a better way. The total area of the holes I plan to create is only about half that provided by modern PVC ventilated soffit strips but I think it might be enough. Things have probably been like this for many years and the condensation doesn't appear to have caused any damage yet apart from a little surface mould which wipes off OK so I'm hoping that I can provide enough ventilation to cure it. If anyone's interested there's a couple of photos at and I'd welcome any suggestions.

Reply to
Mike Clarke

I'd imagine that once the mortar/stone mix gets disturbed it will break free quite easily. You could use a steel drift and club hammer from outside without much bother. I would be tempted to completely remove the mix between say every 4th rafter and replace with fine mesh to prevent bug entry (and treat myself to an SDS afterwards for my trouble).

Reply to
Toby

Still think tile vents might be worth thinking about... have a look at

formatting link
I've fitted similar vents before to a previous home, and it really wasn't difficult. Best bet would be to take a spare tile (ie like the ones on your roof) to a good builder's merchant and they should be able to match it to the optimum type of vent (there are several different designs).

I would imagine that if you lifted a few tiles on the outside, you'd probably be faced with a layer of roofing felt laid on the rafters, and below that, the timber planks. You'd simply have to cut a suitably sized hole through the planks with a jigsaw or something.

I understand it, the possibilty of the presence of asbestos shouldn't put you off - as far as I'm aware, it could only be potentially dangerous if tiles got broken and fibres were released to the air

David

Reply to
Lobster

Hi,

Wow! Might be worth hiring a kango for a day for a try out if the SDS finds it hard going, if it's better you can always extend the hire.

cheers, Pete.

Reply to
Pete C

Thanks for the suggestion. I hadn't thought of removing it all in one lump instead of bashing air brick sized holes in it. Providing the lump isn't too firmly stuck to the surrounding woodwork this could be an interesting alternative but I'm a bit concerned about the possibility of about half a cubic foot of mortar being bashed inwards and landing on top of the lath and plaster ceiling.

We've just bought the house but not fully moved in yet. I'm not going to be able to give this a try until we get the ladder there when we move in properly in a month or two's time, so I think I'll put this job on the back burner for now.

Reply to
Mike Clarke

The thought of tile vents had crossed my mind but I'd assumed it to be more difficult. Judging by the pictures on the Marley site it certainly looks less daunting than I'd thought.

With a conventional roof I'd be very tempted but I have a suspicion that our roof might present a bit more of a problem. When we bought the house the surveyor's report reckoned that there was no sarking felt and the tiles were just laid on top of the t&g decking. If there are horizontal battens for the tiles there'd need to be some spacers underneath them to allow any water leakage to flow down the roof. Without a closer look I suspect that, if there were battens for the tiles to hook over, the whole roof would be much thicker than it appears to be. If I'm right then each tile is probably individually nailed down and it will be quite tricky to just lift a few (especially since I've never messed around with roof tiles before).

If it's doable then tile vents would be a more elegant solution but, as mentioned in my follow-up to Toby's post, I'm not likely to get our ladder there until we move in properly in a month or two's time, so I think I'll put this job on the back burner for now until I get a better chance to study the tiles at close quarters.

Reply to
Mike Clarke

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.